Influence of a heat flux to ice adhesion force.

The secondary working fluid ice slurry is a solution of water, a freezing point reducing additive like ethanol, glycol or salt and small ice particles. The small ice particles are generated in ice slurry generators. The most commonly used ice slurry generator is the scraped surface ice slurry generator, where ice particles grow on a wall of a heat exchanger. After a growth time the particles are scraped off with a scraper, brush or an orbiting rod. Substantial motor power is required for the scraper in order to peel off the interfacial bonding between the ice particle and the heat exchanger surface. The whole power converts into heat in the ice slurry system and therefore necessitates a higher cooling capacity. The adhesion force between the ice particle and the heat exchanger wall can be reduced with a periodic high heat flux into the interlayer of the bonding. For this research a new method to measure the adhesion force between ice and an aluminum surface during the application of a heat flux was designed and a test rig was built. The method of measurement is shown in the paper. The results of the adhesion force without a heat flux are compared with literature values.

二次工质冰浆（ice slurry）是由水、乙醇、乙二醇或盐类等冰点降低添加剂与微小冰粒组成的溶液。这类微小冰粒在冰浆发生器（ice slurry generator）中生成。当前应用最为广泛的冰浆发生器为刮板式冰浆发生器（scraped surface ice slurry generator），冰粒会在换热器（heat exchanger）的壁面上生长。经过预设生长时长后，冰粒会通过刮片、毛刷或往复运动杆被刮除脱离壁面。为剥离冰粒与换热器表面之间的界面结合力（interfacial bonding），刮除装置需消耗大量电机功率。全部功率会在冰浆系统内转化为热量，因此该系统需要更高的制冷量。通过向冰粒与换热器壁面的结合界面层通入周期性高热流密度（heat flux），可有效降低二者之间的粘附力（adhesion force）。本研究设计了一种可在施加热流条件下测量冰与铝表面粘附力的全新方法，并搭建了试验台架（test rig）。该测量方法已在本文中详细展示。本研究将无热流条件下测得的粘附力结果与已发表文献中的数据进行了对比。